1. Field of the Invention
The present invention relates to a miniature optical head for near-field recording and reproduction, in which a vertical cavity surface emitting laser (VCSEL) and a photodetector are integrated on a slider and optical elements for recording and reproduction are formed over the VCSEL and the photodetector by thin film deposition, and a method of manufacturing the optical head.
2. Description of the Related Art
Magneto-optical recording and reproduction systems, which have a higher recording density than magnetic recording and reproduction systems, such as hard disk drives (HDDs), record information onto magneto-optical recording media by magnetic field modulation, and optically reproduce written information from the media, wherein the magnetic field modulation occurs as the magneto-optical recording media lose magnetism at a temperature higher than the Curie point temperature by radiation of a laser beam from a light source.
Referring to FIG. 1, a common swing arm type of a magneto-optical recording and reproducing system is shown. The magneto-optical recording and reproducing system includes an optical system having optical elements which emit light and receive light reflected from an optical disk 1, a swing arm 21 mounted to enable the arm to pivot relative to a base 10, an actuator 23 which provides a rotating driving force to the swing arm 21, and an optical head 30 mounted at the swing arm 21. The optical disk 1 includes a phase change optical disk, which records and reproduces information by phase change caused by light, and a magneto-optical disk, which records information by magnetic field modulation and reproduces information using light.
As shown in FIGS. 2 and 3, the optical head 30 includes a slider 25 having a sliding portion 25a, which is attached at a suspension (not shown) flexibly extending from the swing arm 21 of FIG. 1, such that it is able to scan the tracks of a magneto-optical disk 1—1 while the sliding portion 25a hovers on air a predetermined distance above the magneto-optical disk 1—1 by dynamic air pressure. An objective lens 31 is installed in the slider 25 to focus incident light to form a light spot on the magneto-optical disk 1—1 to reproduce information therefrom. Coils 37 and 39 provide magnetic field modulation.
The coils 37 and 39 are located between the objective lens 31 and the magneto-optical disk 1—1, and are wound around a pair of magnetic poles 33 and 35 in opposite directions. The magnetic poles 33 and 35 are attached to a surface of the slider 25. The magnetic poles 33 and 35 are parallel to each other and separated by a predetermined distance to allow the passing of light which is focused by the objective lens 31. Information is recorded on the magneto-optical disk 1—1 by horizontal magnetic fields according to the direction of current applied to the coils 37 and 39.
In the optical head 30, having the structure in which the coils 37 and 39 are wound around the magnetic poles 33 and 35 arranged in the horizontal direction below the objective lens 31, there is a limitation in reducing the size. In addition, writing by horizontal magnetic fields lowers the recording efficiency and other performances in near-field recording. Furthermore, winding the coils 37 and 39 around the magnetic poles 33 and 35 is ineffective in terms of assembling characteristics, costs and yields, thereby making mass production thereof difficult.
FIG. 4 illustrates another conventional optical head, which is improved from the structure shown in FIGS. 2 and 3. The slider 25 has a projection 46 with a higher refractive index than the refractive index of air, at the side facing a magneto-optical disk (not shown). A coil 43 having an aperture, which allows passing of light focused by the objective lens 31, receives the projection 46 through the aperture and is attached to the side of the slider which faces the magneto-optical disk. The height of the projection 46 corresponds to the height of the coil 43.
The optical head shown in FIG. 4 is smaller than the optical head shown in FIGS. 2 and 3, and has a higher recording density because it records information by a vertical magnetic field. A disadvantage of the optical head shown in FIG. 4 is in that the coil 43 is attached after the projection 46 is formed in the slider 25, thereby lowering assembling efficiency. Manufacturing a smaller projection is also difficult.
In the conventional optical heads shown in FIGS. 2 through 4, the optical system for emitting light and receiving light reflected from an optical disk is mounted on the actuator, or is separated from the optical heads, thereby increasing the size of the entire recording and writing system. In addition, the structure thereof and the manufacturing process therefor become complicated.